![Sample our Mathematics & Statistics journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5943/TOC-Subject-Sample-2021-Mathematics-Statistics.jpg"})
Abstract
By now, a great deal is known about the contributions of Alan Turing, I. J. Good, Max Newman, and other mathematicians who worked at Bletchley Park during World War II. But what about the other side? Until recently, very little was known about the German mathematicians who aided the Nazi war effort: who were they, where did they work, and what did they do? But now, thanks to the release of a large number of TICOM documents in recent years, an initial picture is beginning to emerge. In this article, we identify the most important mathematicians who worked in the different German cryptologic organizations during the war: who they were, how they were recruited, which organizations they were in, and what they did (when this is known). Although their successes never rivaled those of Bletchley Park, they did have successes, and these were sometimes due to the efforts of mathematicians who went on to have distinguished careers after the war. One question that motivated this study was to understand the reasons for the German communications security meltdown during the war: how they got the Enigma and Tunny security assessments partly right but mostly wrong. As will be seen, this was not due to a lack of talent: some of the very best German mathematicians contributed to their war effort. The answer lies instead in how these potentially very useful assets were actually used (in striking contrast with what happened at Bletchley Park).
Acknowledgments
The authors thank the families of Fritz Dueball and Hermann Föppl for information about these two cryptologists; Claus Taaks for providing copies of the court records of the 1937 Dueball trial; Dr. Ingo Althofer for sharing information about Ralf Lohan; René Stein and Robert Simpson of the National Cryptologic Museum in Maryland for providing us both with documents about Wilhelm Fenner and copies of papers in the David Kahn Collection; Dr. Gerhard Keiper of the Politisches Archiv des Auswärtigen Amts in Berlin for supplying information about several individuals who had worked in Pers Z; Dr. Carsten Lind of the University of Marburg Archive for information about Rudolf Schauffler; Mario Aschoff of the University of Halle-Wittenberg Archive for information about Werner Kunze’s doctoral studies there, and the Heidelberg University Archives for information about Kunze and Horst Schubert. Thanks also to Klaus Schmeh for the assistance of his blog (and one of its readers, Thomas Bosbach) in tracking down the postwar careers of Heinrich Döring and Harry Welsch. Special thanks go to the Departmental Historian of GCHQ and indirectly the Director of GCHQ for agreeing to discretionary disclosure of the TICOM report I-31 prior to its public release. We are also grateful to James Reeds, Reinhard Siegmund-Schultze, and Ralph Erskine for many helpful comments on an initial draft of the manuscript. The first author would like to especially thank the staff of the Politisches Archiv des Auswärtigen Amts in Berlin, whose arrangements and friendly help made his research there a great success.
We would like to thank the Editor and an anonymous referee for their careful reading of the final manuscript.
Notes
1 These six organizations had a variety of customers and – especially in the case of the military ones – supplied information to intelligence services having a much broader scope (e.g., human and technical intelligence), and which they served in various ways. For an excellent overview of the different German intelligence services during WWII together with some discussion of the role signals intelligence played, see David Kahn’s classic Hitler’s Spies (Citation1978).
2 The Wehrmacht (previously the Reichswehr until 1935), was the collective term for the armed forces of Germany, consisting of the Army, Navy, and Air Force. Because each of the three separate services had their own High Command and General Staffs, separate from those of the Wehrmacht, the latter had relatively limited control over the day-to-day operations of the three services. For this reason the limited coordination between OKW/Chi and the three service cryptologic organizations is hardly surprising.
3 For further information about the 20 July 1944 plot to kill Hitler, see Fest (Citation1996); Moorhouse (Citation2006); Jones (Citation2008); and Schrader (Citation2009).
4 EASI provides a convenient synthesis of the information contained in a large number of TICOM reports, some of which have not yet been declassified. It necessarily covers, however, only those reports issued prior to its release in May 1946. One should also “trust but verify” when using it: some statements in it differ from the cited TICOM source.
5 Although a number of the TICOM reports dealt with German Naval cryptology, no volume of EASI is devoted to the German Navy’s signals intelligence efforts. The reasons for this are unclear; perhaps the Army Security Agency thought it more appropriate to leave this to the U.S. Naval Security Group.
6 In 1935 the Reichswehrministerium was ominously renamed the Reichskriegsministerium, or Ministry of War.
7 EASI, Volumes 3 and 4 (both dated 1 May 1946) were written before Fenner was (re)detained. As I-206 notes, “[t]he information available from this source [Fenner] considerably expands and to some extent modifies the history of [OKW/Chi and OKH/Chi] given in [EASI, Volumes 3 and 4].”
8 Fenner’s whereabouts after 1946 are not a matter of public record, although he was in correspondence with Dr. Hüttenhain (see below) as late as 1958, and may have played some role in West German signals intelligence. He died 25 July 1961, in Bad Godesberg, of heart and lung disease. (Source for date, place, and cause of death of Fenner: unpublished letter from his daughter Ilse Fenner to David Kahn, 8 June 1970, National Cryptologic Museum, Kahn papers, DK 63-37; Bonn city archives.)
9 The HWA, Heereswaffenamt, was Army Ordinance; Wa Prüf, Waffenprüfung, the division of the HWA devoted to developing and testing weapons and other devices; Wa Prüf 7, the signals section of Wa Prüf.
10 The Germans identified French systems, codes, and ciphers with the country letter F and a running number. The F110 was a four-digit re-enciphered army field code with an 11 digit repeating additive and indicator 55555; see I-176, p. 2.
11 He also seems to have maintained an interest in cryptology. In 1988, he published an article in the Sitzungsberichte (Minutes), Volume XXIV, of the Wissenschaftliche Gesellschaft an der Johann Wolfgang Goethe-Universität, Frankfurt am Main, with the title: “Kryptologie, Konstruktion und Entzifferung von Geheimschriften.” This was later published as a small pamphlet. It was originally given as a talk on 10 January 1987 to the Gesellschaft.
12 For details of the German attack on this system and their successes against it, see EASI 2, p. 81, and EASI 3, pp. 57–58, citing TICOM I-31, pp. 20–21, I-118, pp. 8–9, and I-124, p. 3. For details of the related British stencil subtractor system, see Erskine and Freeman (Citation2003, pp. 310–313).
13 The formal name of the Wittskiste was the Zahlenwurm-Reduzier-Gerät (I-31, p. 4). Detailed technical information about the Wittskiste is given in the 1955 dissertation of Dipl.-Ing. Willi Jensen, Hilfsgeräte der Kryptographie (Flensburg, Germany, Citation1955). For reasons that are unclear, the thesis was never published. It was initially submitted to Professor Friedrich L. Bauer but he declined to review it because he did not feel competent to do so. Bauer, however, kept his copy of the manuscript and later donated it to the Bayerische Staatsbibliothek.
Jensen worked in OKW/Chi IVb, devoted to cryptanalytic machinery, and is mentioned several times in the TICOM documents.
14 Weber (I-124, p. 3) says that in June–July 1941 the two had worked on “U. S. Diplomatic 5-letter traffic” but were unable to read it.
15 This had consequences. In November 1939, when Hüttenhain returned to Berlin from Frankfurt after leading the successful effort by OKW/Chi to break a French Army code (mentioned earlier), the head of the project on the Army side told him that “in his opinion such a large decyphering task could not be done [by] OKH either now or in the future” (D-60, p. 5).
16 Both Boehm and Steinberg joined In 7/IV on 21 October 1939; Pietsch a month later on 22 November. Boehm received his Ph.D. from Berlin in 1936 on a topic in economics, advisor unknown. He is listed in the MGP but not the Kurzbiographien. A personnel list for In 7/VI (which he later moved to) lists him as having been an Abteilungsleiter (Section Leader) of the Viktoria Versicherungsgesellschaft (a life insurance company). Dr. Pietsch will be discussed below. Steinberg apparently did not have a doctoral degree. He was an insurance mathematician who worked for the Allianz Versicherungsgesellschaft before the war.
17 It is a measure of the disfunctional nature of German cipher security that, in other branches of the German military, the double encipherment of the message setting was still sometimes employed: the Luftwaffe used it for its “Yellow” cipher throughout the Norwegian campaign (which ended in June 1940), and the Navy used it in several cases until mid-1944. For the case of the Yellow cipher, see GCCS (Citation1945a, pp. 58–59).
18 Dr. Buggisch (I-58, p. 3) refers to this change as a “renaming” of In 7/VI.
19 The SM-1 was not a Hagelin machine model per se but a system name adopted by the Germans similar to their name AM-1 for the M-209. The Swedish SM-1 was based on the Hagelin C-38 but used 29 bars instead of the standard 27.
20 Moosburg was previously the prisoner of war camp Stalag VII A. Another prisoner kept at Moosburg was Dr. Stein, who was also not interrogated about his work (at OKW/Chi).
21 Ironically, Dr. McVittie himself became an important cryptanalyst at Bletchley Park. He was an Air Ministry civilian who worked at BP from November 1939 until 1945 in the Air Section of Hut 10. He was the Head of the Meteorological Subsection and BP’s specialist on meteorological ciphers.
22 This work was done in collaboration with Pietsch, Steinberg, and Dr. Werner Schulz, but was abandoned when it was concluded that no attack on the machine was possible without a knowledge of the wheel wirings. Nevertheless, Rinow made a valuable theoretical contribution to this effort: the entry in the In 7/VI Kriegstagebuch for September 1941 recorded that “Private Dr. Rinow performed a thorough probability theoretical investigation on a general problem that plays an important role for decryption work, which led to a satisfying result in the form of a formula. Its computational evaluation resulted in remarkable numerical values of which the practical estimates had given no reliable indication.”
23 Founded in 1936, Deutsche Mathematik had a largely Nazi editorial board and, besides pure mathematics, initially published Nazi propaganda pieces on a purported relationship between mathematics and race, promoting what was termed “German mathematics” and seeking to eliminate supposedly alien Jewish influences from it.
24 https://en.wikipedia.org/wiki/Willi_Rinow (accessed 10 February 2019).
25 Siefert and Threlfall are well known in the topological literature in part because of their book Lehrbuch der Topologie (Seifert and Threlfall Citation1934), still available in both the German original and an English translation.
26 The TICOM documents (as is often the case) only report Döring’s last name, but a promotion list in the war diary for In 7/VI gives his first name as “Heinrich”.
27 In WWII, the German Wachtmeister was an NCO rank roughly equivalent to that of a Technical or Staff Sergeant in the current U.S. Army or NATO rank OR-5.
28 The full name of the T52 was the Siemens & Halske Schlüsselfernschreibmaschine (SFM) T52. The machine was developed by Siemens in the early 1930s, the design based on several German patents issued to Siemens in July 1930. It is probably best described as a Wehrmacht teleprinter cipher machine, even though it was developed by the Army; the Army appears not to have been the main user of this machine, but rather preferred the one they developed themselves, the Lorenz SZ40/42. The primary customers for the Siemens T52 machines were the Air Force, Navy, and Wehrmacht command networks, the Foreign Office, and various Nazi authorities. See Weierud (Citation2005).
29 The identification of the cryptologist Heinrich Döring with the mathematician in the Kurzbiographien is based on the concordance between the information about Döring in a document in the U.K. National Archives, HW 80/49 (GCCS, Citation1945b), and that in the Kurzbiographien.
30 Although willing to talk about his own work, Luzius clearly did not want to create problems for others. As his interrogator drily noted, “He remembered no details of the organization, nor could he recall the name of a single one of his colleagues!” (I-211, p. 1).
31 There was another organization with similar responsibilities, the Funkabwehrdienst, a unit within the sinister Ordnungspolizei (Orpo), which was administratively part of the Ministry of the Interior but headed by SS officers. The situation might be viewed as analogous to that of the Abwehr and the Sicherheitsdienst (SD), the competing intelligence organizations of the Army and SS, respectively. The OKW’s Funküberwachung and Orpo’s Funkabwehrdienst did coordinate their efforts to a considerable extent, however, and were often collectively referred to as the Funkabwehr. The corresponding British organization was the RSS (Radio Security Service, eventually part of MI6).
32 One of the best known of these operations was Das Englandspiel (The England Game) or Unternehmen Nordpol (Operation North Pole). The Abwehr had completely penetrated the SOE network in the Netherlands and enemy agents were picked up as they parachuted into the country; see Giskes (Citation1953), a first-hand account by Abwehr Major Hermann Giskes, who led the operation. More than 50 agents were eventually arrested and most executed at Mauthausen 6–7 September 1944. Warnings by Leo Marks, an SOE cryptographer, that there were clear signs the operation had been compromised were ignored (Marks Citation1998).
33 Referat 12 became operational in August 1942, its first report covering the period 1–31 August 1942. From 1 March 1942 to 31 July 1942, agent systems (Agentenverfahren) were handled by Referats 1 and 7.
34 Vauck is listed on a 1 May 1942 personnel list as Olt. (Oberleutnant, First Lieutenant). He was transferred to In 7/VI on 15 June 1942.
35 CSDIC was the “Combined Services Detailed Interrogation Centre,” a set of facilities run by the British War Office (specifically MI19) between 1940 and 1948.
36 https://tu-dresden.de/ua/dokumentationen/alumni/das-alumni-projekt-des-universitaetsarchivs-der-tu (accessed December 30, 2018).
37 Boehm died sometime before November 1986; see the comment in the Journal of the Institute of Actuaries (1886–1994), Vol. 114, No. 1 (June 1987), pp. 15–19 at p. 18.
38 Selchow was a Hauptmann (captain) in the German Army who was assigned to the staff of the Chief of Communications for the Großen Hauptquartier (GrHQu, the Supreme Headquarters of the German Armed Forces) on 1 August 1917 and appointed the Referent (Section Head) for Interpretation and Encryption. He joined the AA on 1 December 1918, transferred to its Cipher Bureau (Chiffrierbüro) on 26 February 1919, and became head of the unit on 1 October 1919; see also Footnote 47. For further information on Selchow, see I-208 and his entry in the AA’s Biographisches Handbuch (Isphording, Keiper, and Kröger Citation2017); the latter is an invaluable source of information for many of the individuals in Pers Z discussed here. Most sources give Selchow’s first name as “Kurt,” but it appears as “Curt” both on his birth certificate and in his AA biography.
39 The Cipher Bureau became part of the AA’s Department (Abteilung) for Personnel and Administration (Personal und Vertwaltung) on 1 October 1919 and its duties enlarged to include Chiffrier- und Nachrichtenwesen (“Encryption and Communications”). This reconfigured Cipher Bureau was then renamed Referat Z in December 1926. The “S” in Pers ZS stood for Sonderdienst, or “Special Service,” a cover for its sensitive function.
40 Pers Z Chi, design of cryptographic systems, was initially overseen by Erich Langlotz (14 February 1893–22 May 1943) and then Horst Hauthal (3 September 1913–21 April 2002). During the First World War, Langlotz had worked in the Communications Division at Army Headquarters (Chef des Nachrichtenwesens im Großen Hauptquartier). He joined the Foreign Office at the end of 1918 and was put in charge of deploying new ciphers on 1 October 1919. He committed suicide in 1943. Hauthal had studied mathematics, chemistry, and physics at Halle and Berlin before the war and joined the Foreign Office on 28 May 1939. He became the leader of Pers Z Chi in May 1943. After the war Hauthal, Paschke, and Kunze played an important role in Foreign Office cryptology; see van der Meulen (Citation1996, Citation1999). Hauthal received a Ph.D. in Economics from the University of Bonn in 1954, and was later active as a career diplomat.
41 Schauffler even solicited articles for the journal from Hüttenhain, but nothing came of this because Fenner disapproved, regarding it as a security risk (EASI 3, p. 100.)
42 Schauffler was never a student at Marburg. The thesis (accepted 14 September) had been written in 1941 but was not published at the time because of its cryptologic content.
43 National Cryptologic Museum, David Kahn Papers, DK 65–50.
44 Friedrich Ernst Dorn (1848–1916) was a German physicist best known for his work on radium and the co-discovery of radon, one of the emission products of radium; see Wigand (Citation1916). Kunze’s thesis was on the decay products of “radium F,” that is, polonium, itself a decay product of radon.
45 The Halle-Wittenberg University Archives (UAHW, Rep. 46, Nr. 27 and Rep. 21, Nr. 402) show that Kunze was registered at the University from 7 May 1910 to 18 July 1913, passed his oral exam (Rigorosum) on 1 August 1913, and that his thesis (Kunze, Citation1914) was approved for publication by Dorn on 3 March 1914. The thesis was titled Über Zerfallsprodukte des Radium F (“On the decay products of radium F”). Kunze remained at Halle for two additional semesters after passing his oral exam (Winter 1913–1914 and Summer 1914), presumably continuing to work in Dorn’s laboratory.
Kahn’s (Citation1996, p. 436) statement “Kunze had his doctorate in mathematics from the University of Heidelberg” appears to stem from a later misreading of notes he took during his interview with Kunze on 4–5 May 1962 in Bonn (National Cryptologic Museum, Kahn papers, DK 65–49). His suggestion “Kunze may well have been the first mathematician employed in a modern cryptanalytic office” thus appears unwarranted. It is of course true that as a physicist Kunze would have had extensive training in mathematics and, given his study of radioactive decay, likely a considerable knowledge of probability and statistics.
46 The OHL (Oberste Heeresleitung) was the Supreme Army Command, headed by the Chief of Staff of the German Army; the Nachrichtenchef was the Chief Signal Officer. In the German military parlance of the day, the rank of an officer could also be used to designated the officer’s staff (as here) or organization (as in the GdNA).
47 All five were initially assigned to the Politische Nachrichtenstelle (PNS, the Political Information Desk), a new cryptanalytic unit that had just been set up in the AA headed by Dr. Hans Riesser (1887–1969). Selchow initially served as Riesser’s deputy but, after Riesser left for Versailles, the PNS and Cipher Bureau merged and Selchow became head of the combined unit on 1 October 1919; see Grupp (Citation1988, p. 151) and van der Meulen (Citation1996, pp. 150–151), whose account is largely based on Paschke (Citation1957). Selchow knew the others because they had all worked at the Supreme Headquarters of the German Armed Forces (GrHQu) during the war. For Riesser’s later diplomatic career, see his autobiography (Riesser Citation1962).
48 Horst Hauthal, the head of Pers Z Chi, shared this opinion: “Er war wohl unser bester Analytiker” (letter to David Kahn, 28 September 1983, National Cryptologic Museum, David Kahn papers, DK 65-64).
49 Hans Rohrbach, in: Verzeichnis der Professorinnen und Professoren der Universität Mainz. URI: http://gutenberg-biographics.ub.uni-mainz.de/id/e5a284c4-7cfa-4e5c-941d-63c55ea94999. (Accessed 25 August 2018)
50 In general, former intelligence officers have to submit such material for prepublication review and approval before publishing it, but in the aftermath of the defeat of the Nazi state, this was apparently no longer a concern for Dr. Rohrbach. Curiously, the paper was published by FIAT (the U.S. Office of Military Government for Germany (United States): Field Information Agency, Technical). Presumably, had the U.S. Army Security Agency (or its 1947 successor AFSA, the Armed Forces Security Agency) been consulted beforehand one assumes it would have objected to publication.
51 EASI 6, p. 2, lamented the absence of other such reports from Pers ZS personnel, noting that immediately after the war the practice of asking the German cryptologists “to do extensive ‘homework,’ that is, write papers, as detailed as possible and in their own words, was not fully developed.” It describes I-89, the sole exception, as “a most significant document from the cryptographic point of view,” adding that even it “was issued with an apology for its preparation.” This last comment was diplomatic. What it is alluding to is a note at the beginning of the report added by Major William P. Bundy: “This [Rohrbach’s report] was probably of no value. It was assigned to appease vanity and keep people busy” (I-89, p. 2). Why a detailed description of a successful attack on an important U.S. system would not be of interest to TICOM passes understanding. Perhaps Bundy (who had a habit of derisively grading the German cryptologists, see I-58, p. 1 and I-63, paragraph 1) for once felt intellectually challenged by the formidable Professor Rohrbach.
52 Köthe was presumably responsible for Rohrbach’s appointment at Mainz as a Visiting Professor (Gastprofessor) from 1946 to 1951. (Rohrbach had joined the NSDAP in 1937 and may have initially had difficulties finding permanent employment.)
53 A third method, the Spalierverfahren, based on reciprocal bigram tables, was less secure and used for the lowest grade of encrypted traffic (Erskine Citation2003, p. 113).
54 National Cryptologic Museum, David Kahn Papers, DK 65-50.
55 Bieberbach was one of the leading German mathematicians of his time. For an extensive discussion of his role in German mathematics during the 1930s, including his editorship of the journal Deutsche Mathematik, see Mehrtens (Citation1987), Segal (Citation2003, especially pp. 263–288 and Chapter 7).
56 Another interesting connection here is that of the University of Münster and two of its Professors, Heinrich Behnke and Heinrich Scholz. Behnke had connections to three of the individuals mentioned in our study: Hüttenhain had studied under him, Köthe had been his assistant, and he was the Doktorvater of Karl Stein. Further, both Hasenjaeger and Schröter received their doctorates under the supervision of Behnke’s colleague Scholz. Helmut Ulm taught at Münster beginning in 1935; he was helped by Behnke after the war in finding employment.
57 For Regene Lewis, see https://bletchleypark.org.uk/roll-of-honour/5503 (accessed 9 December 2018).
58 National Archives and Records Administration, Record Group 457, Boxes 974–976. Colonel J. G. Seabourne was a colonel in the USAAF (United States Army Air Forces) and chief of its Air Technical Intelligence Team.
59 But despite this apparent lack of professional mathematical talent, the B-Dienst had many talented individuals. One of them, Lt. Hans-Joachim Frowein, deserves special mention. In 1944, concerned about mounting U-boat losses, Lt. Frowein was charged by the Navy with investigating the security of the Naval Enigma. He worked on the problem from July 1944 to January 1945, with an initial staff of two officers and 10 men (although this was later cut down to two men of any ability). Despite Frowein’s previous lack of experience with the device (“I started with no knowledge of the Enigma machine”), within 6 months he was able to find an attack based on a 25 letter crib. Although the German Navy did not undertake significant changes as a result of his theoretical findings (he thought the primary weakness of the Naval Enigma was that the right wheel had only one turnover, which was changed), his work was highly enough regarded for him to be awarded the War Merit Cross. For further details, see I-38, his TICOM interrogation on 14 July 1945.
60 Note the “pet subject” and “almost inevitable comments.” The first makes it clear that this was a subject Buggisch himself brought up on a number of occasions; the second that such complaints frequently came up in interrogations of other cryptologists as well.
61 For example, when Dr. Fricke asked his interrogators if any German raster ciphers had been solved, because, although thought to be secure if properly used, he did not know if they had been compromised by operator usage, his interrogators told him “it would be impossible for us to give him an answer” (I-20, p. 3).
62 All three had undergraduate degrees in mathematics and taught mathematics in high school. Kullback and Sinkov each went on to a Ph.D. in mathematics (Sinkov in 1933, Kullback in 1934) within a few years of joining the SIS in 1930.
63 Turing had been recruited by GCCS no later than the summer of 1938, when he took a course in cryptanalysis they gave. Another mathematician, Peter Twinn, who worked with Turing and Dilly Knox on early Enigma problems, joined GCCS full time in early February 1939. Similarly, the Swedes also began to hire mathematicians for cryptological work shortly before the outbreak of war. Arne Beurling was contacted by the Swedish signals intelligence agency in early 1939 and asked to take a course in cryptology and help out with their cryptological problems; see Beckman (Citation2002).
64 In the original version of the SZ40, none of the wheels moved irregularly; see I-45, pp. 16–17. Hüttenhain and Fricke referred to this as the “SZ 40 (old type),” noting “the security of this type was not great.” I-45, a report written by Hüttenhain and Fricke at the request of TICOM, is of great interest because it documents in considerable detail that German cryptologists were aware of the insecurities present in the earlier versions of the encryption devices used by the different branches of the German Armed Forces.
65 For details of the attack on the SZ40, see Zabell (Citation2015). It can be argued that the case of the Enigma was not so much a response to a perceived insecurity in the machine but intended rather as an improvement on the rotor machine principle. If Chiffriermaschinen Aktiengesellschaft (ChiMaAG – the Enigma manufacturer) had had their way, it is possible a pluggable reflector might have been introduced as early as 1927. But although ChiMaAG had ideas about how to make the machine more secure, both the Reichswehr and the Army’s Cipher Bureau had their own agenda and politics. For more information on the early history of the Army’s adoption of the Enigma, see Ostwald and Weierud (Citation2016).
66 New machines were in fact under development, such as the Menzer machines SG 39 and SG 41, both designs that, if implemented, would have given the Allies major problems; see Mowry (Citation1983). Both developments, however, were initiated after the war had started and this put all kinds of obstacles in their path. Increasing priority was put on war material needed at the front and restrictions on these became increasingly severe as the war progressed. Another problem was the sheer challenge of introducing a new system in a secure way in an increasingly shifting and confused war situation. It is doubtful the Germans would have been able to achieve such changes on a large scale even if they had wanted to.
67 The “East Medal,” Medaille “Winterschlacht im Osten 1941/42,” was awarded for service on the Eastern Front during the winter campaign of 1941/1942. There were a number of qualifications to receive the award, including severe frostbite of a limb.
68 The Diplom was the standard undergraduate degree in the sciences in Germany at that time. Given a university’s curriculum, it could take anywhere from 4 to 6 years. Although a first degree, it is often viewed as more the equivalent of today’s Master’s.
69 The Föppls were members of a remarkably accomplished family. Ludwig’s father August Otto Föppl (1854–1924) was a Professor of Mechanics and Statics at the Technical University of Munich; he is known for the Föppl-von Kármán equations, and is thought to have had some influence on Einstein’s early views on special relativity. He had only three graduate students, but one of them — the applied mathematician and engineer Ludwig Prandtl (1875–1953) — more than made up for this: the MGP lists Prandtl as having 87 students and 3721 descendants. Ludwig Föppl’s brother Otto Föppl (1885–1963) was an engineer and Professor of Applied Mechanics at the Technical University of Braunschweig for 30 years. Both Otto and his sister Gertrud were closely connected with Prandtl: Otto was his assistant from 1909 to 1911, and Gertrud became his wife. Ludwig’s grandson Martin Samuels received a Ph.D. in Military Studies from the University of Manchester, has had a career in the British public service, and is the author of (Samuels, Citation2016).
70 The information in this paragraph about Dr. Schulz’s time in In 7/VI is largely drawn from entries in the In 7/VI Kriegstagebuch.
71 Lohan’s advisor was Hilda Pollaczek-Geiringer, the later wife of Richard von Mises. Both Geiringer and von Mises left Germany in 1933 when the Nazis came to power, and so it was necessary to replace Geiringer with the pro forma advisors Klose and Schmidt.
72 We owe some of the information contained in this paragraph, including the reference to “Rumpelstilzchen,” Hilda Geiringer’s role as Lohan’s advisor, and a CV originating with the German Foreign Office, as well as useful background, to the generosity of Professor Dr. Ingo Althöfer of the Friedrich-Schiller-Universität Jena.
73 Stern’s first name appears as Gustav in the court records, but there is no question that this is in reality Gustave Stern (1914–1988), also known as Gérard Sandoz. He escaped via Denmark to France where, after the war, he became one of the leading French experts on Germany. Much later, he wrote an autobiography, Gérard Sandoz: Ein Leben für die Verständigung (Sandoz Citation1990). See also Sandvoß (Citation1996, pp. 95–98).
74 For further information on Walter Herz, see Humboldt-Universität zu Berlin (Citation2010, pp. 23–26).
75 The information relating to the 1937 legal proceedings against Dueball is taken from contemporary court records, copies of which were kindly provided to us by Claus Taaks.
76 It is interesting to note that even Dr. Buggisch did not know the first names of many of the top cryptanalysts in OKH and OKW; see I-176, pp. 6–10.
77 The Sonderführer, or “Special Leader,” was a rank given to civilians with special skills (for example, in medicine or foreign languages) who were drafted into the Wehrmacht in order to capitalize on such expertise. Such individuals were usually not trained as soldiers and did not enjoy (until 1942) either the power of command or discipline that officers of standard military rank did. There were different ranks of Sonderführer; for example, a Sonderführer (Z) was equivalent to the standard military rank of either Leutnant or Oberleutnant (NATO rank OF-1); a Sonderführer (G), Welsch’s rank, was equivalent to that of an Unteroffizier (OR-4).
78 The sources for the above information in this section are documents from the TICOM files T2755–T2767 in the TICOM collection at the German Foreign Office, Bestand Rückgabe TICOM, Politisches Archiv des Auswärtigen Amts, Berlin.